Electrostatic painting systems are known in which the articles painted are electrically charged. Typically, articles are carried through a painting zone by a conveyor with the articles and article carriers isolated from electrical ground. In the painting zone a charged conductor extends along the conveyor path. A charge collector on the article carrier is spaced from the charged conductor and an electric charge is transferred to the carrier and thus to the article supported therefrom. The electric potential on the conductor may be of the order of 75 kV to 100 kV. An undesirable discharge or arcing may occur from the charged conductor. This condition is aggravated by the presence of dirt, paint particles or the like. It is known to enclose the charged conductor in a housing and to blow air through the housing thus minimizing the build-up of charged particles. In prior systems, the air flow around the charged conductor is turbulent or nonuniform. Outside air, which may contain paint particles, is drawn into the enclosure. Swirls or eddies form allowing charged paint particles and other contaminants to enter the field of the charged conductor and to be deposited on the conductor and on the supporting structure therefor. This causes undesirable coating of the charged conductor and inhibits ionization of the air surrounding the conductor and charge transfer to the charge collector on the article carrier. The voltage gradient between the conductor and the collector may become excessive in the absence of ionization of the air and disruptive sparking may occur. Conversely, if the air around the conductor is contained, the concentration of ionized particles may become excessive, lowering the resistance to ground and causing an undesirable current flow to the collector or to ground.